Question

A bike completes two rounds of a circular track of radius 140 m in 5 minutes and 52 seconds.Find the average speed of the bike?

Answer 1

▶ Solution :

Given :

▪ No. of revolutions = 2

▪ Radius of circular path = 140m

▪ Time interval = 5min and 52sec

To Find :

▪ Average speed of the bike.

Concept :

✴ Average speed is defined as the ratio of total distance covered to the total time taken.

✴ Average speed is a scalar quantity.

✴ It has only magnitude.

Conversion :

✒ 1min = 60sec

✒ 5min = 5×60 = 300s

✒ Total time = 300+52 = 352s

Calculation :

$\implies\sf\:Av.\:speed=\dfrac{2\times 2\pi R}{t}\\ \\ \implies\sf\:Av.\:speed=\dfrac{2\times (2)(3.14)(140)}{352}\\ \\ \implies\sf\:Av.\:speed=\dfrac{1758.4}{352}\\ \\ \implies\boxed{\bf{\purple{Av.\:speed=5\:mps}}}$

Answer 2

Answer:

5 m/s

Explanation:

r = 140 m

t = 5 min 52 sec = 300+52= 352 sec.

Since , it is a circular path taking 2 rounds , Distance d = 2 * circumference

d= 2 * 2 pi r = 4 * 22 / 7 * 140

Avg speed = 4 * 22 / 7 * 140  

                     ------------------------(upon)

                     352

=  440 / 88 = 5 m/s